Real-time phishing and lookalike-domain detection for your browser, with inline warnings on Gmail email links.
Users
5
−3 in 30 days
Rating
5.0 / 5
unchanged in 30 days
Ratings
1
0 in 30 days
Store rank
#244K
#204K among extensions
Version
1.0.0
updated 14 May 2026
Users
monthly, 5 months
Latest, 15 Oct 2026:5 usersMove the mouse over the chart for any month
Ratings count
monthly, 5 months
Latest, 15 Oct 2026:1 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About Kestrel
Kestrel warns you about phishing and lookalike websites, including links inside emails, before you click.
How it works
- Detects domain lookalikes: when you visit a site whose name resembles a known brand (paypa1.com, cosico.com, fedex1.com), a site you visit often (netfl1x.com vs your real netflix.com), or a domain you've added to your personal protected-brand list, Kestrel shows a full-width warning banner explaining why.
- Scans email links in Gmail: badges suspicious links inline and shows a banner at the top of the message. Click any badge to see the specific reason ("Says paypal.com but actually goes to example.com", "bit.ly is a URL shortener").
- Combines local heuristics with Google Safe Browsing for known malware and phishing sites.
Privacy
- Your browsing history stays on your device. Kestrel reads it to build a local in-memory index of sites you visit, and never transmits it.
- Email scanning reads only link URLs and the sender's From address. Message text, attachments, and subjects are never read or uploaded.
- Only the current URL is sent to Google Safe Browsing for reputation lookups, the same lookup Chrome's built-in Safe Browsing performs.
- You control the trust list: dismiss any warning you disagree with, or remove sites from the local index from the popup.